Video recorders have become useful in a wide range of commercial and entertainment fields. A key component in such recorders is one or more video "heads", which are used to record or playback information on an appropriate recording medium.
The head itself is a delicate mechanism which protrudes through a surrounding drum surface usually no more than 0.003 inch. As the recorder is used the head gradually wears down, until eventually the head must be replaced. By measuring the amount of head protrusion from its surrounding surface, the amount of remaining head life can be estimated, and it is possible to inexpensively predict the optimum point at which the head should be replaced without having to wait for a total wearout failure.
Presently the manufacturers of some brands and models of video recorders provide a unique means for measuring this head protrusion and wear. For each of these the manufacturer knows precisely where the head is positioned relative to the video recorder frame and provides a series of precision mounting holes for a uniquely designed head protrusion gauge. Since the relative position of the head is known precisely the head protrusion gauge need only be a simple, single point indicator mounted on a unique mounting stand.
Unfortunately for the service technician who is interested in servicing more than one brand of video recorder, each manufacturer's head protrusion gauge is unique and cannot generally be used to measure head wear on other video recorders due to the physical incompatibility. If an attempt is made to make use of such an incompatible gauge the likely result is not only an inaccurate measurement which thus either over or under estimates head wear, but also the possible total destruction of the delicate head requiring an expensive and possibly unnecessary replacement.